The situation when The refrigerator turns off loudlycan unbalance any owner of household appliances. A sudden knock, rumble or sharp click as the compressor completes its cycle is often perceived as a harbinger of serious failure. However, this sound does not always indicate a critical malfunction that requires immediate replacement of the unit. In most cases, the reason lies in the design features or wear of individual damper elements.
Understanding the physics of the process helps to correctly assess the scale of the problem. When the engine stops, the inertia of the moving parts can cause vibration in the housing if the shock absorption system is broken. Also, a characteristic sound can be produced starting relay, which opens the electrical circuit. It is important not to panic, but to listen carefully to the nature of the sound and the frequency of its occurrence.
In this article we will analyze in detail the main causes of extraneous noise when equipment is turned off. You will learn how to distinguish normal operation from a sign of breakdown, which components require attention and when it is really necessary to call a technician. A sharp metallic clang when the engine stops in 80% of cases indicates wear on the rubber bushings of the compressor mounting.
Physics of the process: why sound occurs when stopping
Work The refrigeration unit is built on cyclic compression and expansion of the refrigerant. When the thermostat detects that the set temperature has been reached, it sends a signal to turn off the compressor. At this moment, the pressure in the system is high, and the moving parts of the piston group have a certain inertia. A sudden stop of the engine causes vibrations that are transmitted to the body.
If the equipment is installed correctly and all fastenings are intact, these vibrations are damped silently. However, over time, materials age. Rubber loses its elasticity, plastic elements dry out, and metal connections may weaken. It is these changes that lead to the fact that the normal shutdown process is accompanied by audible noise.
Particular attention should be paid to the type of compressor. In inverter models, the stop occurs smoothly, so loud sounds are not typical for them. If you have a classic linear compressor, then the relay click and vibration when stopping is part of the operating cycle, which should normally be quiet.
⚠️ Attention: If a loud sound is accompanied by vibration of the entire body, which is transmitted to the floor or adjacent furniture, you need to check it urgently horizontal installation of equipment. Prolonged operation in a skewed state will lead to destruction of the condenser tubes.
It is important to distinguish the nature of the sound. A dull knock usually indicates a mechanical contact of the elements, and a loud click indicates electrical processes in the relay. Understanding this difference will help you more accurately describe the problem to a specialist or find a solution yourself.
Wear of damper bushings and compressor mounts
The most common reason the refrigerator knocks when turned offis wear of rubber shock absorbers. The compressor is not tightly screwed to a metal base, but hangs on special springs or rests on rubber bushings. Their task is to dampen the vibration of a running motor and soften the inertial jerk when it stops.
Over time, the rubber drys out, cracks or completely collapses. As a result, the metal frame of the compressor may hit the refrigerator body or the base frame when stopped. This causes that loud bang that scares users. In some cases, it may be necessary to replace not only the bushings, but also the suspension springs themselves.
To diagnose this malfunction, partial disassembly of the rear wall is often required. A visual inspection will show the condition of the rubber. If it turns into crumbs or loses its shape, replacement is required. Ignoring the problem will lead to vibration starting to destroy the soldering of copper tubes.
☑️ Diagnostics of compressor mounts
Replacing bushings is a procedure available to an experienced technician. It is worth carrying out it yourself only if you have the skills to work with the tool, since the compressor is heavy and requires careful handling. Incorrect installation of new parts can cause the noise to become even louder.
Faults in the starting relay and electrical parts
Another reason for loud sounds is starting relay. This small unit is responsible for starting and shutting down the engine. Inside the relay there is a coil and contacts that open the circuit when the motor reaches a certain speed. At the moment of opening, a spark and a characteristic click may occur.
If the relay is faulty or selected incorrectly (for example, after a previous repair), the click can be very loud, similar to a blow. The cause may also be sticking of contacts, when opening does not occur instantly, but with a delay and rattling. This creates a series of rapid clicks before turning off completely.
Relay diagnostics are often carried out by exclusion. The technician can temporarily replace the unit with a known-good analogue. If the loud sound disappears, the problem is solved. It is important to use original spare parts or high-quality analogues that match the power of your compressor.
| Symptom | Probable cause | Sound character | Required actions |
|---|---|---|---|
| Single loud click | Normal operation of the relay | Clear, short | No repair required |
| Series of clicks | Sticking relay contacts | Crackling, rattling | Replacing the start relay |
| Thud knock | Worn compressor bushings | Low-frequency knocking | Replacing shock absorbers |
| Metal clanging | Tubes touching the body | Ringing, sharp | Bending of tubes, insulation |
It is worth noting that electrical problems can be dangerous. If you hear a crackling sound or feel a burning smell along with the sounds of shutdown, you should stop using the equipment until a specialist arrives.
Is it possible to temporarily seal the relay with electrical tape?
No, this is absolutely not allowed. The start relay must breathe and cool. Insulation will cause overheating, melting of the housing and possible fire. In addition, this will not eliminate the cause of the loud sound.
Vibration of pipelines and contact with the body
The refrigeration system is a closed circuit of copper tubes through which refrigerant circulates. When the compressor operates, pressure pulses pass through the tubes, causing them to vibrate slightly. In a new refrigerator, the tubes are secured perfectly, but over time the fastenings can become loose, or the copper itself can become dislodged due to micro-movements during heating and cooling cycles.
If the tube gets too close to the refrigerator body or compressor, residual vibration causes it to hit the metal when the motor is turned off. This causes a ringing, unpleasant sound. Often this happens precisely at the moment of attenuation of the oscillations, that is, immediately after switching off.
To eliminate this problem, the master carefully bends the tubes, increasing the gap. Special soundproofing tape or rubber gaskets can also be used. The main thing is not to damage the thin walls of the copper tubes, as this will lead to freon leakage.
Sometimes the source of sound is not the external, but the internal tube running inside the cabinet. In this case, diagnosis is more difficult and requires experience. The sound can be transmitted through the metal and seem to be knocking from the outside.
⚠️ Attention: Straightening the tubes yourself without skill can lead to them breaking. A pinched tube will disrupt the circulation of freon, which will require expensive repairs with refilling the system.
The impact of improper installation on the noise level
Often users look for complex technical reasons, forgetting about trivial things. If the refrigerator hums loudly and turns off with a blow, it may simply be installed incorrectly. The legs of the equipment must ensure a stable position and no distortions.
Check the horizontal installation using a building level. If the floor is uneven, use adjustable feet. It is also important that the refrigerator does not touch the wall, furniture or other objects. The gap at the back and sides should be at least 5-10 cm for normal air circulation and absence of resonance.
Try to rock the refrigerator slightly. If it wobbles, adjust the front legs. Often, one incorrectly unscrewed support becomes the reason that all the vibration of the unit is transmitted to the floor and intensifies when the motor stops.
When urgent refrigerator repairs are needed
A loud sound when turned off does not always require immediate attention. However, there are signs that cannot be ignored. If equipment failure to cool food is added to the noise, this indicates a serious breakdown of the compressor or a refrigerant leak.
Also an alarming signal is the constant operation of the motor without shutdowns or, conversely, too frequent on-off cycles. In such cases, a loud sound when stopping is only a concomitant symptom of a deeper problem in the thermoregulation system or electrical system.
If you notice that the rear grill of the refrigerator (condenser) does not heat or, on the contrary, is heated unevenly, this requires diagnosis by a specialist. Delay can lead to combustion of the compressor, the replacement of which is often not economically feasible.
Prevention of noisy operation of equipment
In order for your refrigerator to operate quietly for many years, it is important to follow the operating rules. Inspect the rear of the unit regularly, at least once a year. Remove dust from the condenser grille, check that the tubes have not moved.
Make sure that food and dishes are placed inside the refrigerator so as not to touch the walls. Vibration of shelves and contents can also increase the overall background noise, creating the illusion of a motor malfunction.
Do not overload the equipment. Working at the limit leads to overheating of the compressor and increased vibration. Compliance with temperature conditions and loading rules will extend the life of the unit and maintain silence in your kitchen.
Why did the old refrigerator start to turn off loudly, although it used to work quietly?
With age, all materials wear out. Rubber shock absorbers become tanned, the clearances in the compressor bearings increase, and the tube fastenings weaken. This is a natural aging process of equipment, which leads to increased noise during operation.
Is it possible to lubricate a compressor to make it work more quietly?
No, modern compressors are sealed and do not require lubrication during operation. Opening the compressor housing will allow moisture and air to enter, which is guaranteed to damage it. Only external rubbing metal parts can be lubricated if they are identified during diagnostics.
Is it dangerous to continue to use the refrigerator if it knocks loudly?
For a short time - not dangerous, but undesirable. Long-term operation with damaged shock absorption leads to microcracks in the soldering of tubes and freon leakage. In addition, constant vibration can damage other components. It is better to eliminate the cause of the noise at the first opportunity.
Does the shutdown volume depend on the amount of food in the refrigerator?
Indirectly - yes. A full refrigerator stays cold longer, so the compressor turns on less often, but runs longer. An empty refrigerator turns on more often. Frequent start-stop cycles increase the number of times you hear the shutdown sound, but loading has little effect on the volume of the sound itself.
Do you need to replace the compressor if it turns off loudly?
In most cases, replacing the compressor is not necessary. Loud noise can usually be treated by replacing bushings, relays, or adjusting pipes. The compressor is replaced only if it burns out, jams or loses performance, which is confirmed by pressure and current measurements.